Ultrasonic vibrating surgical instruments for cutting and coagulating tissue have been disclosed previously in many publications, for example, see U.S. Pat. No. 2,714,890. The benefits from these ultrasonically-operated instruments include enhanced cutting speed, simultaneous hemostasis and cutting, freedom from electrical hazards and smoke, and less build-up of eschar and other material on the blade. To our knowledge, and with one exception, prior ultrasonic surgical devices require the operator to press the ultrasonically vibrating blade directly against the tissue with sufficient pressure to effectively couple ultrasonic energy to that tissue. An example of such device is described and illustrated in prior U.S. patent applications Ser. Nos. 07/670,186, filed Mar. 15, 1991 and 07/828,697, filed Feb. 3, 1992, of common assignee herewith. In both applications, the disclosed ultrasonic surgical device uses an ultrasonically-vibrated surgical blade to cut and coagulate. In those particular disclosures, the ultrasonic surgical instrument is adapted for endoscopic use and, in both cases, employs a handpiece which carries the ultrasonic power generating element, a blade coupler for mounting a surgical blade, and a blade coupler extension, i.e., a solid shaft, interconnecting the handpiece and the blade coupler for transmitting ultrasonic energy from the power source through the blade coupler extension to the blade coupler and blade. The blade coupler extension is disposed in an extension tube and is provided in lengths in integer multiples of the half-wavelength of axial vibration at the frequency of the ultrasonic energy generated by the power source. Isolation mounts are employed along the blade coupler extension at positions of minimal axial ultrasonic activity or nodes to avoid dissipation or damping out of the ultrasonic energy transmitted from the power source to the blade. The disclosures of these two applications are incorporated herein by reference.
While such instruments as disclosed in those two applications have been found eminently satisfactory, there are limitations with respect to their use, as well as the use of other ultrasonic surgical instruments. For example, prior ultrasonic surgical devices, including those of the two prior applications, have limited ability to apply blade-to-tissue pressure when the tissue is soft and loosely supported. Substantial pressure is necessary to effectively couple ultrasonic energy to the tissue. This inability to grasp the tissue results in a further inability to full coapt tissue surfaces while applying ultrasonic energy, leading to less-than-desired hemostasis and tissue joining.
The use of a clamp mechanism to press tissue against an ultrasonic blade can overcome these deficiencies. A clamp mechanism disclosed as useful in an ultrasonic surgical device has been described in U.S. Pat. Nos. 3,636,943 and 3,862,630 to Balamuth. Generally, however, the Balamuth device, as disclosed in those patents, does not coagulate and cut sufficiently fast, and lacks versatility in that it cannot be used to cut/coagulate without the clamp because access to the blade is blocked by the clamp, requires the blade to be replaced to change the blend of cutting versus coagulating, i.e., only one blade edge is available at any one time, and has a large tip which limits its usefulness as a tool for grasping and blunt dissecting.